Electrostatically driven distributor

ABSTRACT

This disclosure relates generally to rotary atomizers of the type used in painting and coating operations, and more particularly to simple and inexpensive driving mechanisms for rotating such atomizers. The present invention is embodied in apparatus including an atomizing unit comprising a rotary atomizer mechanically coupled and electrically connected to an electrostatic motor in a manner in which a common high voltage charge will drive the atomizer to atomize the coating material and will charge the atomized particles. In one advantageous form of the apparatus of the invention, the electrostatic motor and the atomizer are integrated as a common unit in the form of curved, hollow horn-shaped members mounted on a common sleeve.

United States Patent Edward O. Norris P.0. Box 4157, Westport, Conn; 06607 [2]] Appl. No. 749,164

[22] Filed July 31, 1968 [45] Patented Mar. 30, 1971 172] Inventor I54] ELECTROSTATICALLY DRIVEN DISTRIBUTOR 17 Claims, 8 Drawing Figs.

1521 us. or 239/15, 239/ 3 [5| 1 Int. Cl B05b 5/04 [50] Field of Search 239/16, 3

[56] References Cited UNITED STATES PATENTS 2,900,602 8/1959 Stettler 324/137 2,901,177 8/1959 Norris 239/224X 3,442,688 5/1969 Pettigrew 239/15X II III! eam OTHER REFERENCES PRACTICAL PHYSICS by Millikan & Gale, pp 235, 236. A copy is in the Scientific Library of the Patent Office Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-John J. Love An0rneyMandeville and Schweitzer ABSTRACT: This disclosure relates generally to rotary atomizers of the type used in painting and coating operations, and more particularly to simple and inexpensive driving mechanisms for rotating such atomizers. The present invention is embodied in apparatus including an atomizing unit comprising a rotary atomizer mechanically coupled and electrically connected to an electrostatic motor in a manner in which a common high voltage charge will drive the atomizer to atomize the coating material and will charge the atomized particles. 1n one advantageous form of the apparatus of the invention, the electrostatic motor and the atomizer are integrated as a common unit in the form of curved, hollow homshaped members mounted on a common sleeve.

PatentedMa'rch 30,1971 p 3,572,589

5 Sheefs-Sheet 1 /0 6 fan A RD G A 53 L965:

2 BY 777M ATTORNEY Y Patented March so, 1971 3,572,589

3 Sheets-Sheet 2 INVENTOR 01444 190 O. MORE/S WW Mn ATTORNE Patenid March 30, 1971 S Sheets-Sheet 3 VOL 7A E INVENTOR 501444190 0 A/O/P/P/S BY 7 7M await 1w ATTORNEYS electrostatic force.

ELECTROSTATICALLY DRIVEN DISTRIBUTOR This application is related to my application Ser. No. 455,205 filed May 12, 1965, which is a continuation-in-part of my application Ser. No. 302,513frled Aug. 16, 1963, which in turn is a continuation-in-part of my application Ser. No. 97,481 filed Mar. 22, 1961 for Electrostatically Driven Distributor.

An object is to provide novel and improved means for driving such atomizers.

Another object is to provide a rotary atomizer of the above type wherein a rotary distributor is coupled to an electrostatic repulsion motor in a manner to drive the atomizer and charge the particles to be sprayed from a single high voltage source.

Another object is to provide a rotor of the above type having a low rotational torque drag.

A further object is to provide an atomizer of the above type wherein the material for spraying is distributed uniformly by electrostatic means to the atomizing rotor.

Another object is .to provide an atomizer of the above type having novel and improved spraying characteristics.

Various other objects and advantages will be apparent as the nature of the invention is more fully disclosed.

In one embodiment the rotor comprises a stack of .axial ly spaced atomizing rings enclosing an atomizing chamber into which paint or other material for atomization and spraying is fed from a supply pipe. The rings-are highly charged so that the material is atomized electrostatically as it leaves the supply pipe and forms an atomized mist within the chamber which is attracted to the ringsdue to their charge and is thrownoutwardly from the rings by a combination of centrifugal and The rotor is mounted on a miniature ball bearing of .low drag and by a magnetic repulsion bearing having substantially no frictional drag so that it is free to rotate with a minimum of force. A plurality of electrostatically charged rearwardly directed discharge horns carried by the rotor provide the driv ing force.

Thus the rotor is driven by the same electrostatic charge which assists the atomization.

DESCRIPTION OF DRAWINGS The nature of the invention will be better understood from the following description, taken in connection with the accompanying drawings in which a specific embodiment has been set forth for purposes of illustration.

In the drawings:

FIG. 1 is a longitudinal section through a rotary atomizer embodying the invention;

FIG. 2 is a transverse section taken on the line 2-2 of FIG. I; and

FIG. 3 is a broken detail view illustrating a modified type of suspension for the rotor;

FIG. 4 is a longitudinal section similar to FIG. 1 illustrating a further embodiment of the invention;

FIG. 5 is a transverse section taken on the line 5-5 of FIG. 4 with parts broken away;

FIG. 6 is an enlarged detail sectional view of one of the driving horns;

FIG. 7 is a partial vertical section illustrating the seals and bearing structure; and

FIG. 8 is a partial vertical sectional view illustrating an embodiment having displaced horns.

Referring to the drawings more in detail the atomizer is shown as comprising a series of atomizing rings 1 arranged axially in spaced and stacked relationship and secured by suitable spacers to form an atomizing chamber 2 which is closed at the top and bottom by discs 3 and 4 respectively. The rings '1 are shown as of varying diameters to provide a convex outer periphery adapted to equalize the electrostatic charge plug 7 is recessed to receive the outer race 10 of a miniature ball bearing 9 whose inner race II is secured by a nut [2 to a reduced end of the shaft 8 which is fixed at its upper end to housing 13. Balls 14 roll between the races 10 and 11 to form a low friction bearing for one end of the sleeve 5.

At its upper end the sleeve 5 carries a cup 15 of brass or other nonmagnetic material in which a permanent ring magnet 18 is secured. The magnet 18 is permanently magnetized in a radial direction with its entire outer peripheral face of one polarity and its entire inner peripheral face of the opposite polarity.

A fixed permanent ring magnet 19 is mounted on the housing 13 in radial alignment with the magnet I8 and spaced from the outer surface of the cup 15 toprovide a running clearance. The magnet 19 is also radially polarized with its inner peripheral face of the same polarity as that of the outer peripheral face of the magnet 18 sov that the magnets are held inspace relationship by magnetic repulsion. This provides an antifriction bearing for the upper end of the sleeve 5.

A tube 20 is mounted on the disc 3 in registration with the opening 6 therein, and extends upwardly around the sleeve )5. but is spaced therefrom to provide an annular opening .2l therebetween. The tube 20 is shown as flared outwardly toward the disc 3 so as to return spray particles by centrifugal force into the chamber .2. A paint pipe extends downward through the tube 20 within the annular space 21 and terminates in a curved open end in the chamber 2 to produce a spray as indicated by dotted lines in FIG. 1. The pipe 22 may be made of glass or other nonconducting material and contains a wire 23 which is grounded through a resistor 24.

A flanged ring 28 is carried by the tube 20 at a point spaced from its upper end and carries a plurality of metal horns 29 having rearwardly extended pointed tips 30. A high voltage charge is supplied to the rotor and to the horns 29 by a wire 31 .connected to the shaft 8 and by a pool of liquid mercury contained in a conductive cup 81 and contacting the lower end of the shaft. A voltage of from 50 to kv. is suited for the purpose. This provides an electrostatic discharge from the horns 29 which by repulsion drives the rotor and also charges the rings for atomizing the material from the pipe 22.

Deflector rings 34 are disposed on the discs 3 and 4 to deflect the material away from the end rings and prevent the concentration of material at that point. Such concentration might otherwise occur as the end rings tend to receive a higher electrostatic charge than the central rings. A proper shaping of the stack of rings may reduce this buildup of charge and produce an even spray distribution across the entire face of the distributor.

In this construction the rotor may be comparatively light in weight as it requires no driving motor except the horns 29. The combination of magnetic repulsion bearing and ball bearing provides a minimum friction drag and results in a free running rotor.

Although a specificconstruction has been shown for purposes of illustration it is to be understood that various changes and modifications may be made therein as will be apparent to a person skilled in this art.

In the embodiment of FIG. 3 the sleeve 5a carries at its lower end a bearing cup 40 having a conical upper surface and the shaft 80 is provided at its lower end with bearing needle 41 resting in the conical recess in the cup 40. The elements 40 and 41 may be of the usual jewel bearing type.

In this form the inner magnet ring 18a is disposed around the upper end of the sleeve 5a and is secured on a flange 42 attached to the sleeve. The outer magnet ring 190 is carried by thereover. The lower disc 4 is mounted on a sleeve 5 which exthe housing 13 as shown in the form of FIGS. 1 and 2. The outer peripheral surface of the inner magnet ring is coned or flared outwardly with its larger end at the top and the inner peripheral surface of the outer ring magnet 19a is similarly flared so as to produce a cone-shaped magnetic field having an axial component in a direction to hold the bearing elements 40 and 41 in engagement. The ring magnets thus constitute a thrust bearing as well as an upper spacing bearing and provides a suspension for the rotor having an extremely low friction drag.

in the HO. 3 embodiment, electrical connection to the disc and rotor assembly is made through a mercury pool 82 contained in the lower end of the sleeve 50 and maintaining contact between the sleeve and the shaft 8a. The upper end of the shaft is connected to a power source by a conductor 83.

in the embodiment of FIGS. 4 to 7 a fixed tube 50 which is supported by suitable means, not shown, is formed with a central passage 51 terminating in radial holes 52 and with an external shoulder 53 against which an inner bearing race 54 is held by a nut 55. A sleeve 58 rotates around the tube 50 and at its lower end has a shoulder 59 carrying an outer bearing race 60 secured by a snapring 61 and cooperating with the inner race 54 to provide an antifriction bearing of the ball bearing type. At its upper end the sleeve 58 carries a ring magnet 62 cooperating with a fixed outer ring magnet 63 carried by a flange 64 on a hub 65 which is attached to the tube 50. The ring magnets 62 and 63 fonn an antifriction bearing and centering means as described in connection with the embodiments of FIGS. 1 to 3.

A plurality of hollow driving horns 70 are provided with internal passages 71 and are beveled at their ends to provide pointed tips 72. The horns 70 are disposed in holes 73 in the sleeve 58 with their inner ends having a close fit with the tube 50 and in alignment with the holes 52. Suitable labyrinth seals 74 and 75 are disposed above and below the holes 52 to confine the spray material. A high tension wire 77 is connected to the tube 50 and supplies high tension through a mercury pool 78 to a retaining cup 76 conductively associated with the tube 50. Voltage thus is supplied to the horns 70 and the spray material discharged therefrom.

The operation of this device is similar to that of FIGS. 1 to 3 except that the spray material is supplied through the tube 50 and the holes 52 and 73 to the passages 71 in the horns 70. The material flows along the passages 71 and is discharged from the tips 72. The spray material is charged to the high potential of the horns to assist atomization and is discharged as a spray from the rotor. The reaction of the discharged spray particles assists the repulsion efiect of the electrostatic discharge from the horns to provide a driving torque for the rotor.

The spray material, such as paint or the like, is fed to the tube 50 under a pressure which forces the material through the holes 52 and into the holes 73 of the rotor as the respective holes come into registration. From this point the material is fed through the passages 71 to the tips of the horns from which it is discharged.

The embodiment of FIG. 8 is identical with that abovedescribed except that in FIG. 8 the successive horns are turned alternately in a slightly upward direction and in a slightly downward direction for spreading the spray, whereas the horns of FIGS. 4 to 7 extend in a plane normal to the axis of rotation of the sleeve. The horns may all extend in an upward direction or in a downward direction if desired.

While the present invention has been representatively described in terms of specific preferred embodiments, it is to be understood that certain variations and modifications thereof, within the scope of the inventive principles, will be apparent to those skilled in the art. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention. Furthermore, it is to be understood that the term homs" as used hereinabove and hereafter in the claims is intended to include any group of two or more elements with generally pointed tips affixed to a common hub or sleeve mounted for rotation in the predetermined forward direction about a predetermined axis, the configuration of each of which horns includes radial (with respect to said axis) components, and rearwardly directed (with respect to said predetermined direction of rotation) components and the arrangement of which horns is such that the application of an electric charge thereto will cause the hub or sleeve to rotate in the forward direction by electrostatic repulsion.

Iclaim:

l. A rotary spray distributor comprising:

a. a sleeve;

b. a plurality of stacked rings mounted on said sleeve and enclosing an atomizing chamber;

c. discs closing the top and bottom of said chamber;

d. a tube extending axially from one of said discs to form an annular passage around said sleeve;

e. a material supply pipe extending through said passage into said chamber to supply material thereto for spraying;

f. a fixed shaft;

g. antifriction bearings mounting said sleeve on said shaft for free rotation;

. h. a plurality of rearwardly directed horns mounted on said sleeve;

i. and means supplying a high voltage electric charge to said horns to drive the rotor by electrostatic repulsion; and

j. said last means also supplying said charge to said rings for atomizing the material from said pipe entering said chamber.

2. A rotary atomizer as set forth in claim 1, in which:

a. said sleeve and shaft are mounted on a pair of bearings;

and

b. one of said bearings being a magnetic repulsion bearing composed of inner and outer ring magnets having similarly poled peripheral faces spaced to provide a running clearance therebetween.

3. A rotary atomizer as set forth in claim 1, in which:

a. said sleeve and shaft are mounted on a pair of bearings;

b. one of said bearings being a jewel bearing;

c. the other of said bearings being a magnetic repulsion bearing composed of inner and outer ring magnets having similarly poled peripheral faces spaced to provide a running clearance therebetween; and

d. said peripheral faces being cone shaped and having a taper in a direction to reduce pressure on said jewel bearmg.

4. A rotary atomizer as set forth in claim I, in which (a) said shaft and sleeve have a magnetic repulsion bearing comprising inner and outer ring magnets with adjacent faces having the same polarity and inclined to the axis to provide a thrust having an axial component.

5. A rotary atomizer comprising:

a. a fixed shaft;

b. a sleeve joumaled on said shaft;

c. a set of hollow horns having rearwardly disposed tips mounted on said sleeve;

d. means feeding material to be atomized to said horns;

e. means applying a high potential electric charge to said horns for charging the material discharged from said tips and for forming an electrostatic discharge from the tips of said horns; and

f. said charge being adapted to cause rotation of said horns and sleeve due to the repulsion efiect of said discharge and the reaction of the atomized material discharged from said horns.

6. A rotary atomizer as set forth in claim 5. in which:

a. said shaft is formed with an internal passage for said spray material; and

b. said shaft and sleeve are formed with registering holes for the supply of said material from said internal passages to said horns.

7. A rotary atomizer as set forth in claim 6, in which:

a. a high voltage electrical lead is connected to said shaft;

and

b. said shaft is connected by a contained mercury pool to said sleeve for supplying the charging potential thereto.

8. A rotary atomizer as set forth in claim 5, in which (a) said sleeve is mounted on antifriction bearings, one of which is in the form of a pair of concentric magnetic rings having a running clearance and adapted to center said shaft by magnetic repulsion.

9. A rotary atomizer comprising:

a. a fixed shaft having an axial passage therein for spray material;

b. a sleeve mounted to rotate on said shaft and having antifriction bearings and having a plurality of circumferentially spaced openings for the passage of spray material;

c. said shaft having corresponding radial openings registering with the openings in said sleeve as the latter rotates;

d. a plurality of rearwardly curved hollow horns having bases disposed in registration with the sleeve openings and having tips at their rearward ends;

e. said horns having passages for the feeding of said spray material from their base ends to said tips for discharge therefrom as an atomized spray; and

f. and means supplying a high potential electric charge to said horns adapted to charge the material discharged from said tips for assisting in the atomization thereof and for producing an electrostatic discharge from said tips suited to cause rotation of said sleeve by the repulsion effeet.

10. A rotary atomizer as set forth in claim 9, in which (a) said horns lie in a plane normal to the axis of said sleeve.

11. A rotary atomizer as set forth in claim 9, in which (a) said horns are disposed at an angle to the plane normal to the axis of said sleeve.

12. A rotary atomizer as set forth in claim 9, in which (a) the tips of successive horns are disposed on opposite sides of a plane normal to the axis of said sleeve.

13. A rotary atomizer comprising:

a. a fixed shaft;

b. a sleeve mounted for rotation on said shaft and having antifriction bearings at least one of which is in the form of a pair of magnetic rings positioned to hold said sleeve centered by magnetic repulsion, and the other of which is adapted to prevent axial displacement of said sleeve;

c. a plurality of curved horns carried by said sleeve and having rearwardly displaced tips;

d. said shaft, sleeve and horns being composed of electrically conducting material, a high potential electric lead connected to said shaft, and means interconnecting said shaft and sleeve for thereby applying said high potential to said horns for discharge from the tips thereof;

e. said discharge being adapted to cause rotation of said sleeve by its repulsion effect;

f. said sleeve and horns comprising a rotor, said rotor having means forming passages along which spray material is fed to said tips as the rotor rotates; and

g. material feed means adapted to feed material for spraying to said passages whereby the material receives an electric charge as it is discharged from said tips.

14. A rotary atomizer as set forth in claim 13, in which (a) the material supply means includes a fixed duet disposed interiorly of said passages and communicating therewith.

15. A rotary atomizer as set forth in claim 13, in which (a) sealing means is provided to prevent passage of said spray material to said bearings.

16. A rotary atomizer comprising:

a. a shaft means definitive of a predetennined axis of rotation;

b. sleeve means joumaled on said shaft means for rotation in a predetermined forward direction; I

c. a plurality of hornlike rotor means including rearwardly disposed generally sharp tips mounted on said sleeve means;

d. means for applying a high potential electric charge to said hornlike rotor means for charging the material discharged from an atomization means and for creating a field of electrostatic discharge adjacent the sharp tips of said hornlike rotor means;

e. atomization means adapted to introduce atomized particles into said field;

f. means for feeding material to be atomized to said atomization means; and

g. said field thereby being adapted to cause rotation of said sleeve through the re ulsion effect of said electrostatic discharge and said ield being adapted to charge in- 

1. A rotary spray distributor comprising: a. a sleeve; b. a plurality of stacked rings mounted on said sleeve and enclosing an atomizing chamber; c. discs closing the top and bottom of said chamber; d. a tube extending axially from one of said discs to form an annular passage around said sleeve; e. a material supply pipe extending through said passage into said chamber to supply material thereto for spraying; f. a fixed shaft; g. antifriction bearings mounting said sleeve on said shaft for free rotation; h. a plurality of rearwardly directed horns mounted on said sleeve; i. and means supplying a high voltage electric charge to said horns to drive the rotor by electrostatic repulsion; and j. said last means also supplying said charge to said rings for atomizing the material from said pipe entering said chamber.
 2. A rotary atomizer as set forth in claim 1, in which: a. said sleeve and shaft are mounted on a pair of bearings; and b. one of said bearings being a magnetic repulsion bearing composed of inner and outer ring magnets having similarly poled peripheral faces spaced to provide a running clearance therebetween.
 3. A rotary atomizer as set forth in claim 1, in which: a. said sleeve and shaft are mounted on a pair of bearings; b. one of said bearings being a jewel bearing; c. the other of said bearings being a magnetic repulsion bearing composed of inner and outer ring magnets having similarly poled peripheral faces spaced to provide a running clearance therebetween; and d. said peripheral faces being cone shaped and having a taper in a direction to reduce pressure on said jewel bearing.
 4. A rotary atomizer as set forth in claim 1, in which (a) said shaft and sleeve have a magnetic repulsion bearing comprising inner and outer ring magnets with adjacent faces having the same polarity and inclined to the axis to provide a thrust having an axial component.
 5. A rotary atomizer comprising: a. a fixed shaft; b. a sleeve journaled on said shaft; c. a set of hollow horns having rearwardly disposed tips mounted on said sleeve; d. means feeding material to be atomized to said horns; e. means applying a high potential electric charge to said horns for charging the material discharged from Said tips and for forming an electrostatic discharge from the tips of said horns; and f. said charge being adapted to cause rotation of said horns and sleeve due to the repulsion effect of said discharge and the reaction of the atomized material discharged from said horns.
 6. A rotary atomizer as set forth in claim 5, in which: a. said shaft is formed with an internal passage for said spray material; and b. said shaft and sleeve are formed with registering holes for the supply of said material from said internal passages to said horns.
 7. A rotary atomizer as set forth in claim 6, in which: a. a high voltage electrical lead is connected to said shaft; and b. said shaft is connected by a contained mercury pool to said sleeve for supplying the charging potential thereto.
 8. A rotary atomizer as set forth in claim 5, in which (a) said sleeve is mounted on antifriction bearings, one of which is in the form of a pair of concentric magnetic rings having a running clearance and adapted to center said shaft by magnetic repulsion.
 9. A rotary atomizer comprising: a. a fixed shaft having an axial passage therein for spray material; b. a sleeve mounted to rotate on said shaft and having antifriction bearings and having a plurality of circumferentially spaced openings for the passage of spray material; c. said shaft having corresponding radial openings registering with the openings in said sleeve as the latter rotates; d. a plurality of rearwardly curved hollow horns having bases disposed in registration with the sleeve openings and having tips at their rearward ends; e. said horns having passages for the feeding of said spray material from their base ends to said tips for discharge therefrom as an atomized spray; and f. and means supplying a high potential electric charge to said horns adapted to charge the material discharged from said tips for assisting in the atomization thereof and for producing an electrostatic discharge from said tips suited to cause rotation of said sleeve by the repulsion effect.
 10. A rotary atomizer as set forth in claim 9, in which (a) said horns lie in a plane normal to the axis of said sleeve.
 11. A rotary atomizer as set forth in claim 9, in which (a) said horns are disposed at an angle to the plane normal to the axis of said sleeve.
 12. A rotary atomizer as set forth in claim 9, in which (a) the tips of successive horns are disposed on opposite sides of a plane normal to the axis of said sleeve.
 13. A rotary atomizer comprising: a. a fixed shaft; b. a sleeve mounted for rotation on said shaft and having antifriction bearings at least one of which is in the form of a pair of magnetic rings positioned to hold said sleeve centered by magnetic repulsion, and the other of which is adapted to prevent axial displacement of said sleeve; c. a plurality of curved horns carried by said sleeve and having rearwardly displaced tips; d. said shaft, sleeve and horns being composed of electrically conducting material, a high potential electric lead connected to said shaft, and means interconnecting said shaft and sleeve for thereby applying said high potential to said horns for discharge from the tips thereof; e. said discharge being adapted to cause rotation of said sleeve by its repulsion effect; f. said sleeve and horns comprising a rotor, said rotor having means forming passages along which spray material is fed to said tips as the rotor rotates; and g. material feed means adapted to feed material for spraying to said passages whereby the material receives an electric charge as it is discharged from said tips.
 14. A rotary atomizer as set forth in claim 13, in which (a) the material supply means includes a fixed duct disposed interiorly of said passages and communicating therewith.
 15. A rotary atomizer as set forth in claim 13, in which (a) sealing means is provided to prevent passage of said spray material to said bearings.
 16. A rotary atomizer comprising: a. a shaft means definitive of a predetermined axis of rotation; b. sleeve means journaled on said shaft means for rotation in a predetermined forward direction; c. a plurality of hornlike rotor means including rearwardly disposed generally sharp tips mounted on said sleeve means; d. means for applying a high potential electric charge to said hornlike rotor means for charging the material discharged from an atomization means and for creating a field of electrostatic discharge adjacent the sharp tips of said hornlike rotor means; e. atomization means adapted to introduce atomized particles into said field; f. means for feeding material to be atomized to said atomization means; and g. said field thereby being adapted to cause rotation of said sleeve through the repulsion effect of said electrostatic discharge and said field being adapted to charge introduced atomized particles.
 17. The rotary atomizer of claim 16, in which: a. said hornlike rotor means and said atomization means comprise integral elements; and b. said integral elements are hollow. 